Problem: $ \left(\dfrac{64}{27}\right)^{-\frac{2}{3}}$
Answer: $= \left(\dfrac{27}{64}\right)^{\frac{2}{3}}$ $= \left(\left(\dfrac{27}{64}\right)^{\frac{1}{3}}\right)^{2}$ To simplify $\left(\dfrac{27}{64}\right)^{\frac{1}{3}}$ , figure out what goes in the blank: $\left(? \right)^{3}=\dfrac{27}{64}$ To simplify $\left(\dfrac{27}{64}\right)^{\frac{1}{3}}$ , figure out what goes in the blank: $\left({\dfrac{3}{4}}\right)^{3}=\dfrac{27}{64}$ so $ \left(\dfrac{27}{64}\right)^{\frac{1}{3}}=\dfrac{3}{4}$ So $\left(\dfrac{27}{64}\right)^{\frac{2}{3}}=\left(\left(\dfrac{27}{64}\right)^{\frac{1}{3}}\right)^{2}=\left(\dfrac{3}{4}\right)^{2}$ $= \left(\dfrac{3}{4}\right)\cdot\left(\dfrac{3}{4}\right)$ $= \dfrac{9}{16}$